package 股票;

public class Solution121 {
    public int maxProfit(int[] prices) {
        if (prices == null || prices.length == 0) {
            return 0;
        }
        int[][] dp = new int[prices.length][2];
        dp[0][0] = 0;
        dp[0][1] = -prices[0];
        for (int i = 1; i < prices.length; i++) {
            /*最多钱的卖出*/
            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);
            /*最少钱的买进*/
            dp[i][1] = Math.max(dp[i - 1][1],  -prices[i]);
        }

        return dp[prices.length - 1][0];
    }


    public int maxProfit2(int[] prices) {
        if (prices == null || prices.length == 0) {
            return 0;
        }
        int[][] dp = new int[prices.length][2];
        dp[0][0] = 0;
        dp[0][1] = -prices[0];
        for (int i = 1; i < prices.length; i++) {

            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);

            dp[i][1] = Math.max(dp[i - 1][1], dp[i - 1][0] - prices[i]);
        }

        return dp[prices.length - 1][0];
    }

    public int minCostToMoveChips(int[] chips) {
        int length=chips.length;
        if(length%2==0){
            return length/2;
        }else{
            return (length-1)/2;
        }
    }


}
